In the technical field of antennas, there is an ever growing need for broadband conformal antennas to not only reduce the number of antennas utilized to cover a broad range of frequencies (VHF and UHF), but also to reduce the visual and RF signatures associated with communication and radar systems. Prior art conformal metallic antennas have narrow bandwidth and low efficiency.
A magnetic current, instead of an electric current, may be used as the primary source of radiation in antennas, such as in antennas with very high permeabilities. Such antennas with a magnetic current as the primary source of radiation will be referred to as “true magnetic” antennas with a relative permeability μr>>1 and dielectric constant ϵr>1. Advantageously, when mounting true magnetic antennas on a conducting ground plane, there is no loss of gain or efficiency. The radiating magnetic current is aided by the image current produced by the metallic ground plane.
True magnetic antennas use permeable materials as their radiating elements and are ideal for electrically small conformal antenna applications. True magnetic antennas have many applications that cannot be obtained by prior art antennas, therefore the optimum feeding of these antennas is of great interest.
Magnetic antennas may use solenoid feeds to enhance antenna performance. However, previous solenoid feeds have significant phase delays, which lead to destructive interference. In order to reduce this phase shift interference, previous solenoid feed systems require complicated feed networks and/or elaborate matching circuits.
Therefore, systems and methods for enhancing antenna performance, such as peak gain and current distribution, and eliminating phase delays and other issues, are highly desirable.